As an acoustic device using two exciters, a device described in Patent Literature 1 is disclosed. In Patent Literature 1, the exciters are respectively fixed on facing surfaces of a cylindrical body, and one exciter is caused to vibrate on the basis of a signal obtained by inverting only a phase of a frequency component in which a standing wave occurs in a first acoustic signal. Furthermore, the other exciter is caused to vibrate on the basis of a signal obtained by inverting only a phase of a frequency component in which a standing wave occurs in a second acoustic signal.